(Not Applicable.)
The field of the invention relates to internal combustion engines, more particularly to housings for covering compact internal combustion engines, such as those used in lawn mowers, snow blowers, generators and the like.
Internal combustion engines are used to convert chemical energy to mechanical or electrical energy for a wide variety of applications. Some internal combustion engines are compact and have one or two small cylinders for use in low to moderate power applications, while others have a higher number of large cylinders for use in high power applications. Engines of any type or size generate a great deal of heat due to the combustion process. Large engines, such as in an automobile, are typically enclosed in an isolated area, such as under the hood and in front of a firewall of a car. As such, large engines are ordinarily out of reach of their users or passersby. However, compact engines are typically used in devices, such as lawn mowers, in which the engines are openly accessible. Thus, compact internal combustion engines often have a guard or shield over the engine to reduce the risk of someone contacting a hot engine and being burnt.
In some cases, such as in lawn mowers, the engine is partially or totally covered by a housing usually made of plastic or some other non-conducting material. Engines have a number of sub-assemblies and systems that may also radiate heat. Typically, separate housings cover, for example, the air filtration system and the cooling system. Additionally, baffles to direct air to the engine cooling system and air intake are usually attached to the housings. Each of these housings and baffles require fastening systems, which increases part count and complexity of manufacture and assembly. The plurality of housings typically must be disassembled and reattached using tools. Moreover, the housings for sub-systems are often nested beneath the main or other housings, such that multiple housings may have to be removed to access a single sub-system. Multiple housings and cumbersome fastening systems render servicing the engine and its subassemblies difficult.
Accordingly, an improved housing for a compact internal combustion engine is needed.
The present invention provides an improved housing for an internal combustion engine having a cover of one piece construction. Removing the cover allows access to multiple systems of the engine needed to be maintained. The cover is held to an engine cradle or mounting frame by resilient straps allowing the cover to be assembled and removed easily without the use of tools.
Specifically, the cover has a top side and downwardly extending side walls sized to cover a fixed cradle containing the engine. At least one of the side walls defines an outwardly opening recessed groove extending from a bottom edge to a catch. A strap fits within the recessed groove which has a fixed end attached to the engine cradle and a free end removably engageable with the cover catch. Engagement of the catch with the free end of the strap secures the cover to the engine cradle.
The strap is preferably a rubber material and the free end includes a tab that engages the catch. The tab has a projecting end for grasping the strap to engage and disengage the strap from the cover. The strap is stretchable and sized so that it is under tension when engaged with the catch so as to bias the cover toward the engine cradle. In one embodiment, the cover includes a plurality of recessed grooves each retaining a stretchable strap for securing the cover to the engine cradle. Moreover, the engine cradle has side walls defining inwardly opening longitudinal slots in which the stretchable straps are in part disposed.
The cover includes a baffle at the top side defining a convex opening having smooth inwardly tapered walls to direct air into the housing in an essentially non-turbulent condition. Curved raised surfaces in the baffle serve to direct air into the opening. In one embodiment, a bezel attached to the top side of the cover retains a screen for covering the opening. The cover encloses an engine air filter and includes a hold-down extending down from the top side of the cover for limiting the movement of the air filter. Preferably, the cover is a glass-filled polypropylene material.
In one preferred form, the housing of the present invention includes an engine cradle defining a volume for containing the engine and fixed with respect to the engine. A removable cover having a top side and downwardly extending side walls covers the engine cradle. The side walls define a plurality of recessed grooves extending from a bottom edge to a plurality of catches. A plurality of stretchable straps are disposed in the recessed grooves with fixed ends attached to the engine cradle and opposite free ends defining tabs that engage the catches to bias the cover to the engine cradle. The cover also defines an air baffle at the top side having a nozzle defined by a convex circumferential surface having a narrowing diameter from top to bottom so that air drawn into engine volume through the nozzle is essentially non-turbulent state.
One object and advantage of the present invention is to provide an engine housing allowing easy access to the engine. This is accomplished by using a single cover enclosing the entire engine. Because the entire engine is enclosed by a single cover, additional covers are not required for sub-systems of the engine. This also allows an operator to quickly and easily examine at a glance parts of the engine other than the area being serviced.
Another object and advantage of the present invention is to provide a cover that can be assembled and removed without using tools. This is accomplished by using stretchable tie down straps which engage catches in the cover to bias the cover to the engine cradle.
Yet another object and advantage of this invention is to provide a housing that provides increased air flow to the engine. This is accomplished by directing air to the engine cooling system in an essentially non-turbulent state. The convex opening in the top of the cover acts as a venturi opening providing high-speed laminar air flow to the engine.
Still another object and advantage of this invention is to provide a housing that helps to secure a removable air cleaner. This is accomplished by a vertical wall integrally depending from the top of the cover to restrain the movement of the air cleaner.
A further advantage of the present invention is that the cover is made of a glass-filled polypropylene making it durable and resistant to thermal conduction.
The foregoing and other objects and advantages of the invention will appear from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown by way of illustration a preferred embodiment of the invention.